基于高品质因子光纤谐振腔的布里渊激光线宽压缩研究  

Brillouin Laser Linewidth Compression Research Based on Ultra-High-Quality-Factor Fiber Resonator

作　　者：杨艳平 刘诗涵 周恒 Yang Yanping;Liu Shihan;Zhou Heng(Key Lab of Optical Fiber Sensing and Communication Networks,School of Information and Communication Engineering,University of Electronic Science and Technology of China,Chengdu 611731,Sichuan,China)

机构地区：[1]电子科技大学信息与通信工程学院光纤传感与通信教育部重点实验室,四川成都611731

出　　处：《光学学报》2024年第20期151-156,共6页Acta Optica Sinica

基　　金：国家自然科学基金(62375043,62001086);四川省科技计划项目(2022YFSY0062)。

摘　　要：光纤布里渊激光是实现窄线宽激光器的重要技术方案,光纤谐振腔的品质因子(Q值)越高,产生的布里渊激光线宽越窄。通过增加光纤谐振腔长度同时减小其自由频谱宽度,将耦合Q值提升到10^(10)以上。利用超高精度的PoundDrever-Hall(PDH)锁定技术,在光纤谐振腔自由频谱宽度远低于布里渊增益带宽的情况下,实现单纵模布里渊激光的产生,其边模抑制比大于70 d B。此外,采用参考激光外差法、延时自外差法、共腔激光外差法三种方式对光纤布里渊激光器的线宽进行严格测试,实现亚毫赫兹(sub-m Hz)量级的布里渊激光基础线宽。Objective Ultranarrow linewidth lasers have found widespread application in various fields such as precision gyroscopes,optical sensing,coherent optical communication,atomic clocks,and ultrastable microwave generators.Recently,researchers have used stimulated Brillouin scattering(SBS)in ultrahighqualityfactor(Qfactor)fiber resonators as an effective method for linewidth compression.By increasing the Qfactor and Stokes light power in a long fiber cavity,the linewidth of Brillouin lasers can be compressed,resulting in a narrower output beam.However,achieving stable singlelongitudinalmode operation with a long fiber cavity can be challenging due to limitations of the free spectral range(FSR),relative to the gain bandwidth of SBS.The Vernier effect in a compound cavity can address this challenge and achieve singlelongitudinalmode operation with narrow linewidth,though this approach requires precise control of cavity lengths and can be complex.In the present study,we described a novel approach that combines the PoundDreverHall(PDH)locking technique with the stimulated Brillouin effect in an ultrahighQfactor fiber resonator and achieved a significantly reduced linewidth for Brillouin lasers,reaching the submHz level.We hope that this research will promote the development of narrow linewidth Brillouin lasers and drive progress in several key fields,including optical communication,optical spectrum analysis,and optical sensing.Methods We combine the PoundDreverHall(PDH)locking technique with the stimulated Brillouin effect in an ultrahighQfactor fiber resonator to compress the linewidth of Brillouin lasers.Initially,we increase the coupled Qfactor to over 10^(10) by lengthening the fiber resonator and simultaneously reducing its free spectral range.In addition,thermal and mechanical isolation treatments are applied to the fiber resonator with foam and aluminum boxes to mitigate the influence of external environmental factors.The highprecision PDH locking technique is then used to generate a singlelongitudinalmode Brilloui

关 键 词：激光器 受激布里渊散射 窄线宽 单纵模 光纤谐振腔 

分 类 号：TN242[电子电信—物理电子学]